Saturday, October 06, 2007

Walrus on the move

Thousands of walrus have appeared on Alaska's northwest coast in what conservationists are calling a dramatic consequence of global warming melting the Arctic sea ice.

Alaska's walrus, especially breeding females, in summer and fall are usually found on the Arctic ice pack. But the lowest summer ice cap on record put sea ice far north of the outer continental shelf, the shallow, life-rich shelf of ocean bottom.

Walrus feed on clams, snails and other bottom dwellers. Given the choice between an ice platform over water beyond their 630-foot diving range or gathering spots on shore, thousands of walrus picked Alaska's rocky beaches.

Starting in July, several thousand walrus abandoned the ice pack for gathering spots known as haul outs on a remote, 300-mile stretch of Alaska coastline. Biologists fear walrus will suffer nutritional stress if they are concentrated on shoreline rather than spread over thousands of miles of sea ice.

Walrus need either ice or land to rest. Unlike seals, they cannot swim indefinitely and must pause after foraging. As the ice edge melts and moves north in spring and summer, sea ice gives calves a platform on which to rest while females dive to feed. Lack of sea ice is at the heart of upcoming problems for walrus, and the problem of maintaining ice is way beyond us.

U.S. Marine Mammal Commission

1 comment:

Dapoppins said...

I hate to hear things like this. I really do. Cause I want to fix it for them.